Project Summary. PreCyte is developing the Indicator Cell Assay Platform (iCAP) as a broadly applicable and inexpensive blood-based assay that can be used for the early detection of disease, disease stage stratification, prognosis and predicting response to therapy for a variety of diseases. The iCAP uses cultured, standardized cells as biosensors, capitalizing on the ability of cells to respond to disease signals present in serum with exquisite sensitivity, as opposed to traditional assays that rely on direct detection of molecules in blood. Developing the iCAP involves exposing cultured cells to serum from normal or diseased subjects, measuring a global differential response pattern, and using it to build a reliable disease classifier based on the expression of a small number of genes. Deploying the iCAP involves measuring only expression of genes that are classifier features using cost-effective tools. We have demonstrated the iCAP for blood-based detection of lung cancer and detection of Alzheimer's disease (AD) at preclinical and early symptomatic stages. In the SBIR Phase II study, conducted in collaboration with the Institute for Systems Biology, Center for Infectious Disease Research, and Seattle institute of Biomedical and Clinical Research, PreCyte has developed an iCAP- AD capable of detecting AD at preclinical and early symptomatic stages in multiple cohorts. For this Phase IIb, we propose to develop and validate a clinical iCAP AD, a high-throughput and inexpensive version of the iCAP for rapidly selecting subjects for clinical trials of AD therapies. From a simple blood test, the clinical AD iCAP will be able to select from a population of subjects 60 years and older, those with either preclinical or early symptomatic AD and specificity against those with non-AD dementia, and may have additional capacity to identify a subset of these candidates who will progress to AD within 2 years. Development and validation of the clinical iCAP-AD will be done in four specific aims: 1) Develop the clinical iCAP-AD, 2) Establish limits for key assay parameters to demonstrate assay robustness, 3) Validate analytical characteristics of the clinical iCAP, and 4) Validate diagnostic characteristics of the clinical iCAP. The goal of this proposal is to mitigate the risks of using a cell-based assay and establish a robust and validated platform for use in selecting subjects for AD clinical trials and patient diagnosis. After implementation in a CLIA environment, this tool will significantly reduce cost and shorten the duration of clinical trials for AD treatments by rapidly selecting early-stage subjects, with potential to identify those who are within 2 years of developing AD. It will also improve success rate of developing an effective treatment for AD as it enables the targeting of patients at preclinical and early symptomatic stages of the disease, which have been demonstrated to be more treatable than later stages, and could also be used for monitoring AD progression and response to treatment.